1. Field of the Invention
The present invention relates to portable computing devices, and more particularly to laptop computers including multiple pointing devices, such as a pointing stick and a glide point, that are operated in concert with proximately located mouse buttons.
2. Related Art
As computer users increasingly navigate through window-based user interfaces, data input devices, such as a mouse, have become standard features on modern computer systems. These data input devices are typically used to move a cursor around a graphical display, and they typically include associated buttons, such as mouse buttons, which are used select and activate graphical objects located under the cursor.
Providing a data input device, such as a mouse, on a portable computing system presents a number of challenges. These portable computing devices, such as laptop computers, are often used on airplanes, buses or trains, where there is no room for an external pointing device such as a mouse to be used. Consequently, different types of pointing devices have been integrated into portable computers, including: pointing sticks, glide points and track balls. The term "pointing device" is used in the specification to refer to any manually operated input device that can be used to move a cursor around a computer display, this includes but is not limited to: a mouse, a track ball, a pointing stick and a glide point.
A pointing stick typically takes the form of a short stick, often with a rubber tip, protruding perpendicularly from the surface of the portable computer. It is often located between keys on a computer keyboard for easy accessibility. If force is applied to the pointing stick in a direction parallel to the surface of the portable computer, the pointing stick will pivot so as to specify a direction relative to the surface of the portable computer. This direction is typically used to move a cursor around the portable computer screen. The pointing stick is typically biased so that it returns to a position perpendicular to the surface of the portable computing device when released.
A glide point is another type of pointing device that typically takes the form of a plate embedded in the portable computer surface that is sensitive to the touch of a finger. A glide point can detect the finger through a variety of means, including capacitive sensors, resistance sensors and pressure sensors. A glide point is typically designed so that when a finger touches the glide point, associated circuitry determines a location on the plate where the finger touches the glide point surface. By "gliding" a finger along the glide point surface, a user can specify a velocity and a direction of travel for a cursor on a graphical display.
A track ball is another type of pointing device that typically takes the form of a ball disposed within a recess in the portable computing device so that the ball is able to freely rotate about its center. By rotating the ball in a particular direction, the user can specify a displacement of the cursor on the graphical display.
Pointing devices such as glide points, pointing sticks and track balls are typically used in conjunction with buttons, as are found on a mouse, to select graphical objects located under the cursor. These buttons are typically located near the pointing device so that the buttons can be operated by the same hand that controls the pointing device.
This gives rise to a problem for portable computing devices that include multiple pointing device, such as for example a pointing stick and a glide point. If the buttons are located near the glide point, the buttons cannot be easily manipulated by a hand while the hand operates the pointing stick. If the buttons are located near the pointing stick, the buttons cannot be easily manipulated by a hand while the hand operates the glide point.
What is needed is portable computing system with multiple pointing devices, such as a pointing stick and a glide point, that provides buttons that can easily be manipulated by a hand that is operating the pointing stick, as well as buttons that can be easily manipulated by a hand that is operating the glide point.